Ninety health, environmental and sporting groups asked the U.S. government Thursday to clamp down on the release of methane gas by the petrochemical industry, asserting that the United States cannot reach its goal for reducing heat-trapping emissions without addressing the issue.

Led by the Clean Air Task Force, the groups asked the Environmental Protection Agency and the Interior Department to develop federal regulations to plug leaks of methane from oil and gas exploration equipment and the industry practice of burning excess methane. The groups are also concerned about leaks of natural gas — which is mainly methane — during transport.

Although it comprised only about 9 percent of U.S. greenhouse gas emissions in 2011, according to the EPA, and breaks down more rapidly, methane is a much more potent heat-trapping substance than carbon dioxide. Its impact on climate change is more than 20 times greater than carbon dioxide's over 100 years.

A study by climate scientists published last month showed that the government may be seriously underestimating the amount of methane discharged into the atmosphere by oil and gas exploration and livestock. It called into question a decision by the EPA this year to reduce its estimate of natural gas emissions nationwide.